1)   SMS and Pager Toolkit 4.1
SMS Control to send and receive SMS messages. Features GSM modems (incl. WaveCom, Multitech), SMPP and SMSC (TAP,XIO,UCP) and GSM phones (incl. Nokia,Siemens,Motorola). Samples for VB.NET, VC#.NET, VC++, Visual Basic, ASP and ASP.NET

 2)   SMS-it 3.3.7
SMS-it allows you to send SMS (Text, pictures, ringtones) to a mobile phone from your computer. It sends through a modem, the internet or an attached mobile phone

 3)   HS GSM SMS C Source Library 1.3
HS GSM SMS is a C source library. It provides a PC based user application with access to a mobile phone's Short Message Service (SMS) function, according to ETSI standards: GSM 07.05 (ETS 300 585) (use of DTE for SMS), GSM 03.40 (SMS)